Protective apparatus for differential fluid meters



April 25, 1950 w, BEIECHER 2,505,456

I PROTECTIVE APPARATUS FOR DIFFERENTIAL FLUID METERS Filed March 4, 1946 u L 15-10 I w a y Fl 6.6

Fl 6. 5 Y INVENTOR.

Y dQHNl MBEECHER ATTORNEX element.

Patented Apr. 25 1950 PROTECTIVE APPARATUS FGR DIFFEREN- TIAL FLUID METERS John W. Beecher, Waterbury, Conn., assignor to The Bristol Company, Waterbury, Cnn., a corporation of Connecticut Application March 4, 1946, Serial No. 651,813

7 Claims.

through conduits.

In a very large proportion of the installations of differential manometers for the purpose of determining the pressure developed across a cons'triction in a pipe line or conduit, the static pressure existing in the piping system is much greater than the maximum differential pressure corresponding to the full range of the instrument. When operating conditions are normal, the manometer is not at any time subjected to a difierential pressure in excess of that to which its measuring range is adapted; and, while the parts of the instrument may be directly subjected -to the static pressure existing in the line, this appears only as a pressure differing from that i I of the surrounding atmosphere, and is easily resisted by the heavy casing of the instrument. So long as the piping system is intact and the rate of flow through the measuring constriction does not greatly exceed that for which the instrument is designed, the pressures applied to the delicate measuring element of the manometer (which may be in the nature of a bellows, a Bourdon spring, or a mercury column) are neutralized, with exception of the differential due to fluid flow through the constriction, which differential is determined by the manometer and may be interpreted as a measure of the rate of flow.

In the installation of flow meters, it is frequently expedient to locate the manometer unit at-a considerable distance from the main pipe line in which the flow is to be determined. The connecting line (generally a pair of relatively small and fragile pipes or tubes) is thus likely to be subjected to mechanical damage or to unauthorized disconnection such as would be highly improbable in the part of the piping system immediately adjacent to the instrument. In the event of such a breakage or accidental disconnection, there is likely to develop either an unbalanced pressure in the manometer or a flow of the measured fluid through the system in such a manner as to set uppressures which may be damaging or even destructive to the manometer It is an object of the present invention to provide means whereby, in the event of development of an excessive differential pressure across a manometer or the like, the meter will be bypassed and the pressures on the two sides of the meter equalized before the differential value can rise to a dangerous magnitude.

It is a further object of the invention to provide means of the aforesaid nature which shall afford a permanent record of the condition responsible for development of the objectionable pressure differential which caused its operation, thereby facilitating a knowledge of the history of an accident or other condition leading up to failure in the piping system.

A still further object of the invention is to provide means of the aforesaid nature which, subsequent to the occurrence of an abnormal condition against which it is effective to protect a delicate meter, and restoration of operating conditions, may with a minimum of manipulation be restored to its normal state of readiness for further failure in the system.

Another object of the invention is to provide means of the aforesaid nature which shall be positive in operation, inexpensive to maintain, and not in itself subject to damage by the conditions against which it is adapted to protect other equipment.

In carrying out the purposes of the invention, it is proposed to provide a device having two separate compartments adapted for communication respectively with the two sides of the differential meter under protection, said compartments being separated by a flexible diaphragm of sufficient strength to resist the maximum normal operating differential pressure, and to include in said compartments mechanical piercing means activated by an abnormal excess of pressure in either compartment over that in the other to puncture said diaphragm and provide a free passage for fluid whereby the pressures prevailing in the compartments will tend to become mutually equal. It is understood that no novelty attends the use of burstable or frangible diaphragms to permit the escape of fluids when exposed to, or developing, pressures in excess of those attending normal operating conditions; and such devices as depend for their functioning upon the rupture of said diaphragms due solely to fluid pressure acting thereon, and setting up stresses beyond their elastic limit. The present invention is distinguished from the prior art in that a diaphragm is forcibly pierced, punctured, or torn by a concentrated stress mechanically applied to a limited Fig. 2 is a fragmentary bottom plan, partly in transverse section, of certain :of the elements shown in Fig. 1.

Figs. 3 and 4 are respectivelyan elevation of .a piercing member and holder and aplan .of the piercing member. 7

Fig. 5 is a connection diagram, to a reduced scale, showing the invention applied to the protection of a differential fluid meter or manometer.

Fig. 6 is a vertical section of a device alternative to that shown in Fig. 1.

Referring to the drawings, I0 and Il designate two similar cup-shaped flanged casings, each having a side opening and an end opening, whereby tubular connections may be made hetween their interiors and apiping or conduit sysj tem, secured together as by bolts i2 passing ...through their juxtaposed flanges to clamp there- 'between a diaphragm I3, thus forming two similar enclosed chambers I4 and i5, sealed and separated from each other by said diaphragm. The

"diaphragm. I3 is formed of thin sheet metal whose properties and proportions are selected in accordance with operating conditionsv and pressures of the apparatus with which the device istoLbe used, and also with respect to the nature of thefluid medium to which said diaphragm may be ex- ,posed. As an example; it;may be said that where gpressure differentials betweensaid chambers will not normally exceed 100 inches of water, the diaphragm may be'formed of sheet aluminum having a thickness of the order of magnitude of .0.0025 inch. The diaphragm I3 is preferably of dished conformation, and is assembled with its convexface'projecting-into the chamber M whereby to have apredetermined relationship to other elements in said chamber-and presently to "be described.

Within the inner edges of the flanges upon the casings I0 and II are formed rabbets in which are fitted clamping rings I1 and 58, respectively, said rings having juxtaposed faces engaging the diaphragm I3 in clamping-relationship, and the latter ring having integral therewith a spider 251 "with a central-portion somewhat depressed from the plane of clamping engagement with said dia phragmyand having a slot 2! 'medially located therein. The structure and disposition of the :spider 20 will be better understood by reference to Figs. 2 and'3 taken in conjunction with Fig. l. fPositioned in the islet 2L and secured therein,

iasiby a set screw 22, is ja' pi'eroing member :23

gsuch that the cutting edges of. said -member lie 'isubstantiallyin the plane .or clamping of the diaphragm I3 against the ring I8.

Valve 4 I.

Mounted within the casing I0 and occupying a considerable portion of the chamber I4 therein is a bellows member 25 havin its interior in communication with the opening in the end wall of said casing and sealed ofi from said chamber I4. Carried by the free end of the bellows member .25 is a mounting block. ZLadaptedto receive a piercing member 28 which may be identical in all respects with the hereinbefore-described 'member 23 and located coaxially therewith. The

member 28 is secured to the block 21 by means of a set screw 29 and is disposed with its principal plane perpendicular to that of the member 23,

both said planes being perpendicular to the clamping plane .upon which the flanges of the casings I0 and II engage the edges of the diaphragm I3 and to each other.

The manner of connecting the device embodying the principle of the invention into a meter piping system for the purpose of protecting a differential meter will be understood by reference to Fig. '5; A pipe or conduit 30 in-which the flow of a fluid is to be determined is provided with-an orifice plate retained in' a flanged clamping portion 31 having conduits 32 and 33 connected to the opposite sides "thereof and to the corresponding ports of a difierential meter 36, which may be of any conventional type'wherein an index or pointer is caused to take up with respect to a graduated scale a measuring-position representative of the pressure differential between said conduits, and therefore of the rate-of flow in said pipe or conduit 30. Theinterior of the bellows member 25 of the protectiveunit, represented by its casings Ill and .II, is placed-in communication with the chamber I5 by means of a pipe 35 (including preferably a union 36 wherebysaid pipe may readily be separated), said pipe being connected to one of the openings in the wall of the casing I I. The other of saidopenings has connected thereto a pipe 3'! which may be placed in communication with the conduit 33 through a shut-01f valve 38. The chamber I l has in communication therewith a pipe '40 connected thereto through the-opening in the side-wall of the 'casing Hi; and said last-named pipe may be connected with the conduit 32 through a shut-oil A manually actuated by-pass valve 32 connected between'the conduits 32, 33 forms a conventional part of such metering systems and provides a means whereby the difierential meter may at any time be relieved of the differential applying the pressures from the conduits 33 and to the c am ers 15 and 4 res e t v ly, the former pressure being 'fiplalied' also; toqthe interior of thebellows member ,25, Thejnteriorparts are so proportioned and adjusted that, with normal variations of differential pressure corresponding 'tothe operating range'of'themeter 34,.the distor- .tion he diaphra m s no annr iab chans d the convex face maintaining, its projection into the chamber is. The bellows memberZE carrying internall the samelprsssure ,asjin the chamber 15, which is normally in excess of thatiin .the chamber it, will tend to expand, carrying the 1 .61 :M due to "i s connectioniifi; in which case the pressure :inthe conduit: would .be applied through the iconduit :33. tonne-side of thermeter 134. gsaidgpressure will also :be :appliedrto the interior .of chamber I i-and,

through the pipe $5,; to the interior .of b ll ws :lmemberyz.

With th redu t n pr ssure in the :c ambroken condu t 19.2, t e excess "pressure n said :10 lows.;.member "w ;.ca, .i e; h me o expand, b neins:th -;pie1i ine-mcm er .28 in o eng g 1 1 61. 1 ith the: convex face o he d agm #3, w ich is at t e same time fo c d fu therinto the chamber Jd by the excess pressure pi'evailing in .the chamberwl. The concentrated stress due to :the sharp points of cthe member fidengaging the material of theydiaphragm 5.3 .willscausesthelatter :to be, punctured; land, with-a diaphragm of su ta y s l ct dmater alrsuch .a -pu11oture, underthe influence.oi-therapplied fluid-pressure, will rapidly. develop into a tear enlargingthe opening between the ,tWo chambers 1130 such anextent as to render-impossibletha continuance-ref any lapf .preciable; pressure differential therebetween. If condit ns s ould be suohthatthe pi r n m m- .ber moves further toward .the chamber is with expansionoithe bellows Zdthediaphragm, if not ,already disintegrated by fiowiofifluidrthroughthe; .openingtherein, will .be forced against the piercing member 13 into theslotgl l thereof, thecu'ttins por o softhe.tw pie cinsm mbersbec min interdisita e to r uc a cruciform. r penin in the diaphragm, which openin under the i ,fiuenceof the escapin flui w ll rapidlvbecom enla ed to an,extentsubs antially to eliminate P es ure differenti l between thechamb em l5. nd co esponding y to reduce th di ierent al aoro s e m ter 3.5:

:Inthee nto he conduit33ibeccmin broken,

with full, p e r rem. m .nsi in .the conduit :32, this pressure, "being'applied to the chamber M andltoithcaconvex,sideof the diaphragm l3 practically unopposed by pressure in the chamber 15, will cause theudiaphragm to buckle and be abruptly forced against the cutting edges of the piercing member 23, puncturing .theidiaphragm as hereinbefore described and permitting it to be ruptured -ancltornto the extent of opening a free passage between the "two chambers and qualizins theprcssu e cmss the meter 5- n'th m .9 th nve t cns s thus fa id e00 esnecessa rafter thec w schemata in p rcinga fith idiaphraam- [3, that the. clerics be dis onn cted,

t p p separated the bolts r m v d, to permit separation ofthe'casings ill-i I, whereupon :the ruptured diaphragm may be removed uponthat of the initial fault in the piping system, as affecting the first engagement between said diaphragm and a piercing member, examination of the removed diaphragm will in many instances serve as a clue to the trouble and, where ct ommunication with the and enlepedhyan w unit- :ns't nature cf the first puncture of the diaphragm will be dependent tl'le plpingihasiundergoneaextensivetdamage; may

iacilitate: ldentificationof ithebriginal failure.

rim-Fig. 6ris zshownian improved form of the invention; specially adapted to ready installation .toiservicingwithaminimum of delay. A cell .50 formedof. metalor the like, substantially cylindrical :iniiorm, :and open :at .one end is provided with a flangedqand :threadedrim 5! adapted "for engagement .closure means presently to :be 0:

described. I Cored onotherwise iformedin the wall rat the cell 5.8. is aspassae .5. providin c m- :munication ibetween .a centrally located opening 5.2 in: the inner end wall of said ceil and an face of thefianged rim 5|. he cell 5.53 are provided with the sidewalls of lqpenings and add adapted to receive tubular connections, the, former providing communication "with" theg-intericr spaceloi the cell and the latter with the passages-5 2. (Centrally positioned within the cell EBIandhaving its interiorspace in communication with the passage 3552 through. open- ;ing 52, is :a bellows member 55 carryingonits ireeaenda mounting block Sdadaptedto receive a piercing memberfid,:vzhich parts may be identical in all respects with the corresponding block 2 l .and memberfi B shown-in Fig. 1.

Acap member .60 havingga flange portion 6| .forrned to cooperate .with the flanged rim 51 .of the cell 50 in providin ta-n enclosure is adapted to be maintainedin fluid-tight. engagement with said cell by the action of. an annular clamping nut fizadapted ,threadedly to engage the thread- ,ed portion of the ,;rim. 5l and clampingly to engage-the flange portion iii of saidcap member.

Formed in the .bodyofthe cap member cl is a short passage 53 communicating with the interior ofsaid cap and'with theoutletEZ" of pas- -sage,52 inthe wall of thecell 56. When assembled, the cap member St is definitely located in .such anangular positionwith respect to the cell :59 thatsaidpassages 52and are in positive register, and maintained in said position by ,meansof dowels-pfidone of which appears in Fig. 6. The cap'member .60 isvrecessed to containa mountin g block carrying a piercing member itfirlhich maybe identical-withthepiercing member 51, the principal planes of said piercing members intersecting atan angle approximating degrees.

Positioned between-the flanges 5i and ii! and clampedthereby is a diaphragm 38, of material and construction-similar to the diaphragm l3, and having in its rim portion such openings as maybe necessaryfor the dowels 5t as well as to permit free communication between the passages 52 and .53. The diaphragm B8 is dished, and is .hositioned with its convex'face toward the intei fior of the cell 5% the piercing members 5? and V 16. being respectivelyadjusted so that the former clears the diaphragm surface under the maximum normal peratingpressure diiierential, and the latter terminates approximatelyin the clamp- .ing plane ofithelflangedrimportions5i and ti.

nclination, theiform of the apparatus shown illEi-lfi i8 .c nnectedintoa metering systemsubantia11y identically with that shown in Fig. l. ITIhcLDiDesS'l and (lilof Fig. 5 would be connected to the openings 5 and 'tt respectively, and all other connections wouldbe made identically with those shown in Fig. 5, care being taken that the opening 54 be connected to the upstream side of the system, or that side having normally the greater of those two pressures whose difierential is to be compared. Under normal conditions, the greater pressure in the cap member 60 will maintain the diaphragm 68 with its convex face projecting into the cell 50 but clearing the piercing member 51. Upon the development of an abnormal excess of said pressure over that within the cell 50, there will take place an action identical with that described in connection with the form of the invention shown in Fig. 1, the cutting edge of the piercing member 51 being forced into the material of the diaphragm 68, puncturing the same and initiating a rupture or tear which will relieve the difierential pressure between that within the cell 50 and that within the cap 60. Similarly, in the event or the pressure within the cell becoming excessive, the diaphragm 58 will buckle and will be brought abruptly into engagement with the piercing member 66, with results as hereinbefore described.

For restoration of service after operation of the form of the invention shown in Fig. 6, it is necessary only to close the valves between the device and the piping system, unscrew the clamping nut 32, and remove the cap member 60. This will expose the diaphragm 68 which may readily be removed and replaced by a new unit.

I claim:

1. Over-pressure release device, comprising a casing, a diaphragm separating the casing into two normally non-communicating chambers, together with connections respectively to said chambers for fluid under difierent pressures, and a first and a second piercing element located respectively upon opposite sides of the diaphragm in the respective chambers, said first element being stationary with respect to said diaphragm and said second element having attached thereto fluid pressure responsive means communicating with the chamber in which said first element is located, to render said second element movable under the influence of pressure prevailing in said last named chamber to pierce the diaphragm when the pressure differential of the pressures prevailing in the respective chambers exceeds a predetermined value, thereby to eliminate substantially the excessive pressure differential.

2. The over-pressure release device as claimed in claim 1, in which the diaphragm is of flexible material.

3. The over-pressure release device as claimed in claim 1, in which the piercing elements are adapted for interdigitated cooperation.

4,. Over-pressure release device, comprising a casing, a diaphragm separating the easing into two normally non-communicating chambers, together with connections respectively to said chambers for fluid under difierent pressures, and pressure responsive means in one of the chambers subject to the pressure in the other chamber and movable in the direction of the separating diaphragm, said means carrying a piercing element to engage and pierce the said diaphragm, when the pressure differential of the pressures prevailing in the respective chambers exceeds a predetermined value, thereby .to eliminate substantially the excessive pressure differential.

5. Over-pressure release device, comprising a casing, a flexible diaphragm separating the casing into two non-communicating chambers, together with connections respectively to said two chambers for fluid under different pressures,

pressure-responsive means in one of the chambers subject to the pressure in the other cham ber and movable in the direction of the separating diaphragm, said means carrying a piercing element to engage and pierce the said diaphragm, when the pressure differential of the pressures prevailing in the respective chambers exceeds a predetermined value, and a stationary piercing element in said other chamber adapted to engage and pierce the said diaphragm when the latter contacts the last-named piercing element upon flexing of the diaphragm under an excessive and reverse pressure differential.

6. Over-pressure release device, comprising a casing, a diaphragm separating the easing into two normally non-communicating chambers, together with connections respectively to said two chambers for fluid under difierent pressures, and

an expansible bellows member in one of the chambers, the interior of said bellows member being connected with the other chamber and the free end of the bellows member being juxtaposed to the separating diaphragm, together with a piercing element secured to said free end adapted to engage and pierce said diaphragm, when the pressure differential of the pressures prevailing in the respective chambers exceeds a predetermined value, thereby to eliminate substantially the excessive pressure differential.

'7. Over-pressure release device, comprising a casing including two separable portions, and an intermediate diaphragm, together with removable means to secure th casing portions to each other and the said diaphragm therebetween to separate the casing into two normally non-communicating chambers, connections being provided respectively to said two chambers for iiuid under different pressures, and a first and a second piercing element located respectively upon opposite sides of the diaphragm in the respective chambers, said first element being stationary with respect to said diaphragm and said second element having attached thereto fluid pressure responsive means communicating with the chamber in which said first element is located, to render said second element movable under the influence of pressure prevailing in said last named chamber to pierce the diaphragm when the pressure differential of the pressures prevailing in the respective chambers exceeds a predetermined value, thereby to eliminate substantially the excessive pressure differential.

JOHN W. BEECI-IER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,951,897 Binckley Mar. 20, 1934 2,225, 20 Huff ..Dec. 17, 194.0 2,320,211 Bloom et a1. May 25, 1943 2,374,523 Beecher Apr. 24, 1945 2,410,310 Smith Oct. 29, 19%

FOREIGN PATENTS Number Country Date 318,550 Germany Feb. 10, 1920 

